Randy Jones, the sheriff's spokesman, said the deputy had obtained permission from the woman to leave her children in the care of a male passenger.
According to Jones, Martinez was arrested after an informant told the sheriff that a library employee was using a stolen Social Security number.
The tip came as state authorities were investigating the Alamance County Health Department, whose employees allegedly had been writing work illness excuses using illegal immigrants' false names. Officials have said they found no evidence of wrongdoing. But Martinez's arrest prompted suspicion among immigration reform advocates that authorities had tracked her through confidential medical records, which the sheriff's office has denied.
Jones said that Martinez had "self-identified" her illegal status by using a dead person's Social Security number. After pleading guilty to misuse of a Social Security number, a felony, Martinez was released Aug. 13 on $25,000 bond and placed under house arrest pending deportation hearings.
After Martinez's arrest, the county began checking all of its new employees against a Department of Homeland Security database to verify Social Security numbers. The Sheriff's Department does not target illegal workers or ask criminal suspects about their immigration status, Jones said, "but we have the legal responsibility to act on allegations of a felony crime."
The problem, said Martinez's lawyer, David B. Smith, it that immigration authorities fail to distinguish between undocumented workers who commit serious crimes and those who live productive, law-abiding lives.
Martinez declined to comment on the case.
But Marilyn Tyler, a retired librarian, called the situation in town "pathetic."
"The sheriff's office is using all this energy and time on one woman to tear her life apart, but why?" she said. "This is a situation where you have to use judgment."
Crystal Williams of the American Immigration Lawyers Assn. said federal authorities fail to exercise the prosecutorial discretion commonly used by local law enforcement. The approach taken by U.S. Immigration and Customs Enforcement, she said, is one of "no discretion whatsoever. . . . If they find anyone in violation, they arrest them."
A 2000 memo from the Immigration and Naturalization Service, the predecessor to ICE, does instruct agents to consider such mitigating factors as long-term U.S. residency, lack of a criminal record and "expressions of opinion" by community members.
